The invention concerns a method for instantiating (representative by a concrete instance) a class having different versions that is defined in an object-oriented programming language.
A (software) agent system essentially has two components, the agent platform and the agent itself. A monitoring and administration tool is often also present as a third component. An agent (also called a robot, wanderer or spider in the Internet) is a program that, equipped with the rights of a particular user, exists unsupervised for a time dependent on the concrete function to be fulfilled, and during this time can meet with other agents and work together with them. So that an agent does not paralyze computer systems in the manner of a virus, it must "identify" itself, and is permitted to have only a finite life span.
In general, two types of agents are distinguished. A stationary agent is executed by only one computer from the beginning of the program up to its end. In contrast, a mobile agent is executed by different computers at different times in its life cycle. An agent platform must exist on the computers that are supposed to be reachable for the agents. This agent platform provides the agent with, among other things, services for migration, (controlled) system access and message transmission and reception. The monitoring and administration tool enables the manual start of agents, the overview of data collected by agents and the display of other items of information concerning the agent system.
During its running time, a system of mobile agents can be distributed to many computers within a network. For this purpose, it is the case both that a platform is necessary at each (node) computer in the network, and that agents, data structures and message objects can move from computer to computer. If, in the course of the software life cycle, errors are detected in one of these (sub-) programs, or if parts of the software are changed for other reasons (e.g. improvement of algorithms, adaptation to changed environment, and, with limitations, change of function as well), then under some circumstances a termination, and, after the corresponding changes, a subsequent restart of the overall system can be required.